The present invention relates to a method for enhancing yeast growth for cell culturing and fermentative bioproduct production, and a nutrient composition for such uses, and a fermentable biomass mixture that contains the nutrient composition.
Microorganisms are used in fermentations to produce many kinds of products, such as ethanol, acetone, butanol, organic acids, lipids, oils, enzymes, proteins, special carbohydrates, antibiotics, and other products. Ethanol production from fermentation of biomass has received significant attention in recent years as a source of alternative fuel or biofuel.
Various additives have been described for use in cell culturing and production processes for fermentations with an objective of improving these operations.
Amartey, S., et al., “Comparison of corn steep liquor with other nutrients in the fermentation of D-xylose by Pichia stipitis CBS 6054.” Biotechnology letters 16.2 (1994): 211-214, describes the use of media containing corn steep liquor as the only source of nitrogen, amino acids, vitamins and other nutrients in the fermentation of D-xylose by a xylose fermenting yeast, and comparatively evaluates the efficacy of the media containing corn steep liquor with other media containing other sources of nitrogen in promoting yeast growth.
U.S. Patent Application Publication No. 2012/0317877 A1 describes a method for biodiesel production by yeast fermentation which uses raw materials including crude glycerol and corn steep liquor.
U.S. Patent Application Publication No. 2013/0084615 A1 describes a method for producing ethanol and yeast protein feed with whey permeate and nutrient source, wherein the method has inoculating, seeding, propagating steps, and fermenting steps. The nutrient source in the inoculating, seeding, and propagating steps is described as containing liquid ammonium phosphate and corn steep liquor, and other components such as urea ammonium nitrate, antibiotics, and hydrogen peroxide.
U.S. Pat. No. 5,843,734 describes an antifoaming agent for a fermentation process, wherein the antifoaming agent is a reaction product that is obtained by adding a specified ratio amount of ethylene oxide and propylene oxide to a mixture of an oil or fat and a polyhydric alcohol, and at least one compound selected from fatty acids, alcohols, polyoxyalkylene polyhydric alcohol ethers, polyoxyalkylene alkyl ethers, polyoxyalkylene fatty acid esters, polyoxyalkylene alkyl ether fatty acid esters, and polyoxyalkylene polymers.
U.S. Pat. No. 6,448,298 B1 describes a defoamer for alcoholic fermentations, wherein the defoamer is an aqueous composition which comprises a polydimethylsiloxane oil, an ethylene oxide/propylene oxide block copolymer, and a silicone/silica blend, in a specified ratio.
U.S. Pat. No. 7,955,826 B2 describes a method and composition for the production of ethanol by a Saccharomyces spp. during fermentation of a feedstock substrate in the fermentation medium which comprises adding an emulsion comprising a monoterpene and a surfactant or combination of surfactants. Surfactants are described that include ethoxylated alcohols, ethoxylated carbohydrates, ethoxylated vegetable oils, polyethyleneglycols (PEG), polypropylene glycols (PPG), monoesters and diesters of PEG and PPG, ethoxylated amines, fatty acids, ethoxylated fatty acids, fatty amides, and fatty diethanolamides, and specific examples of commercial sources of the surfactants.
Previous nutrient based products used in fermentations do not necessarily significantly increase yeast cell number or increase yeast cell viability, budding, and vitality. Previous nutrient products, when used in yeast propagation and fermentation, also do not necessarily increase yeast cell high ethanol concentration tolerance or increase oil extraction. Improved nutrient based products for cell culturing, propagating, and fermentations are needed which can reliably provide for improved results in these and other respects.